Re: [PATCH v3 4/7] gpio: max7360: Add MAX7360 gpio support

[Andy Shevchenko <andriy.shevchenko@intel.com>]

On Wed, Feb 12, 2025 at 01:57:34PM +0100, Mathieu Dubois-Briand wrote:
> On Mon Jan 27, 2025 at 2:07 PM CET, Andy Shevchenko wrote:
> > On Mon, Jan 13, 2025 at 01:42:28PM +0100, Mathieu Dubois-Briand wrote:

...

> > > +	parent = to_platform_device(pdev->dev.parent);
> >
> > Why do you need this? Can't the fwnode be propagated to the children and then
> > the respective APIs to be used?
> 
> I'm not sure to understand this correctly, what do you mean by
> propagating the fwnode to the children?
> 
> Just a quick summary of the situation and what I try to do. The device
> tree looks like this, only keeping the interesting properties:
> 
> io-expander@38 {
>   ...
>   interrupts = <23 IRQ_TYPE_LEVEL_LOW>,
>                <24 IRQ_TYPE_LEVEL_LOW>;
>   interrupt-names = "inti", "intk";
> 
>   max7360_gpio: gpio {
>     ...
>   };
> 
>   max7360_gpo: gpo {
>     ...
>   };
> };
> 
> Our pdev fwnode points either to the "gpio" or "gpo" nodes, the one from
> our parent device points to "io-expander@38". Here we need to get the
> "inti" interrupt from the parent node. What would be the correct way to
> do it?

Ah, I see now. This is being used only for IRQs, but don't you want to call
actually fwnode_irq_get_byname()? It will makes the intention clearer.

...

> > > +	if (of_property_read_u32(pdev->dev.of_node, "ngpios", &ngpios)) {
> > > +		dev_err(&pdev->dev, "Missing ngpios OF property\n");
> > > +		return -ENODEV;
> > > +	}
> >
> > This is not needed, it is already done in GPIOLIB core.
> 
> I believe this is still needed:
> - For gpos, we need the gpio count to correctly set the partition
>   between gpo and keypad columns in max7360_set_gpos_count().

Shouldn't be that done somewhere in the GPIO valid mask initialisation?

> - For gpios, we need the gpio count to setup the IRQs.

Doesn't GPIOLIB parse the property before initializing the IRQ valid mask
and other init callbacks?

-- 
With Best Regards,
Andy Shevchenko